Leaking upstairs window sill? Please help.........

[valleyboy]

Hello Everyone,

I will try and be as brief as I can with this, so here goes.....

The house is approx. 100 year old terrace, window sill is stone.

Following picture shows area where I have the damp problem, this area has begun growing mould and smells like death, has to be cleaned regularly. The room has recently been gutted and re-rendered and plastered etc. The window is also new. Old window was in an awfull state so I had assumed (stupidly) that this was the source of the water ingress. It is now obvious that that was not the case.

I have had a closer look today and scraped all loose paint off the outside sill. There was a lot of loose stone that came away with the paint, a layer around 4mm thick off most of the sill. Picture below shows sill.

As well as this, there is a crack at either side of the sill. Photos below show affected areas.

If I tap the cracked area it sounds hollow (blown), but I cant tell weather this is on the surface like the rest of the sill or if it's because the area under the sill is hollow.

Anyway, in an attempt to solve the problem I have just re-sealed the area along the sill where the base of the PVC window sits (after cleaning out all the old loose crap). I am unsure if pasting lots of silicone on the cracked area will help at all as a temporary fix.

What are your opinions on the source of the leak? Can you recommend a temporary fix? Also, would like to know what the long term solution is?

Any suggestions will be greatly appreciated.

Thanks for reading and appologies for the lengthy post..........I'm sure I said I was going to be brief........harder than it sounds when trying to describe something like this.

P.S. Can't seem to get decent quality images uploaded. I have tried to highlight the effected areas in red, obviously more than happy to send decent pics via email if anybody is really that interested!

Cheers,
Valleyboy

 

[^woody^]

Is this black mould or yellow/brown staining

If its staining then its a leak and you need to locate it.

If its black mould, then you probably have condensation forming on a cold spot.

 

[valleyboy]

Woody, thanks for your response.

The mould is black.

I understand what you are saying but prior to having this room renovated the plaster in this area had blown, when removed (plaster layer only) there was a distinct wet patch (could clearly see this on the rendering) immediately beneath the left hand side of the inner sill. This was around the size of a grapefruit.

Having said that, I do have excessive condensation on the windows and have to wipe them every morning.

 

[^woody^]

Its difficult to see the arrangement of the cill and roof below.

If there are any cracks or open joints then water will get in. If it was getting in to the internal face then there would normally, but not always, be some staining, and large damp patch after rain, and smaller when no rain has occurred. There would also be staining a definite edge to the stained area. Does this happen?

However, water naturally in the cill or wall below can have a cooling effect which leads to local condensation, and this can also only occur during rain so can be mistaken for penetrating moisture.

The cill looks like it has been coated previously, so you may want to re-do it with some thing suitable. And silicone any open edges

If you have a condensation issue then deal with that.

 

[valleyboy]

Ok, thanks for the advice.

With regards to the arrangement of the roof and cill. There is a gap between them of approx. 18 inches. My feeling is that the roof line is too low to cause a problem as far up as the window cill, however I'm no expert.

You mention re-coating. The cill had previously been painted with gloss paint, is this what you are referring to? If not, what would be 'something suitable'? Are you suggesting that it may need coating with cement or something similar?

If this is a condensation issue then I'm not sure that I can really do anything to 'deal with' it. The room is heated, my bathroom has extractor fans fitted, I do not use the radiators to dry clothes etc. If the damp patch is being caused by natural cooling within the wall then I have no clue how to resolve this.

At the moment I have a dehumidifier in the room. I hate this as I feel that this is merely a solution to the symptoms rather than a permanent cure for the cause of the issue.

 

[steven5]

Hi There

I have exactly the same problem did you solve you leak. if so any advise.

Regards
Steve

 

[valleyboy]

No, not solved yet and has come back with a vengance now that the wall are colder! Aaaarggghhh!

 

[steven5]

I have been told possibly the water is running back under then getting in through the brickwork. Silicone will solve this hopefully....


Steve

 

[Richardp]

You'll often find a leak is not where you expect it to be , you may find its coming in above the window and running round the frame and out the bottom making it look like the leak is from there, then putting on the Silicone is trapping it and making it worse, I recently found the source of a leak 6ft away from where it came in, it took ages to find but then I noticed where pointing was loose,the edge of an RSJ, the water was running along it and into the window
richard